Speed controls for aircraft



May 16, 1933- F. w. FINDLEY 1,908,894

SPEED CONTROLS FOR AIRCRAFT Filed May 20, 1930 5 Sheets-Sheet l Fredlfhdiey WMM May 16, 1933. F. w. FINDLEY 1,908,894

SPEED coNfrRoLs FOR AIRCRAFT Filed May 20, 1930 5 sheets-smet 2 VMay 16, 1933.

F. W. FINDLEY SPEED CONTROLS FOR AIRCRAFT 5 Sheets-Sheet 5 Filed May 20, 1930 5 Sheets-Sheet 4 31o/vento@ Fred/MEM@ May 16, 1933- F. w. FINDLEY 1,908,894

SPEED CONTROLS FOR AIRCRAFT Filed. May 20, 1930 5 Sheets-Sheet 5 Patented May 16, 1933 UNITED sTATEsSPATENT oFFlcE FRED FNDLIEY, OF LONGVIEW, W'SHINGTON SPEED CONTROLS FOR AIRCRET Application led May 20,

My invention relates to a control system for automotive vehicles, whereby the force of the driving engine or engines is so applied as to produce the most elicient utilization of the power, substantially without change of speed of the driving engine, and to adjust such application of the driving forces in accord ance with the load or resistance met with under varyin conditions.

More speci cally, my invention relates to a control system intended for aircraft generally, both airplanes and airships, whereby the adjustable-pitch blades of a propeller or propellers are automatically adjusted in accordance with a speed-responsive element, suc-h as an element responsive to air speed, and whereby the .supply of fuel to the engine is variable in response to engine speed changes, or either may be employed alone, whereby the engine may operate, with substantially no change in speed, at the most eiiicient engine Speed, notwithstanding changes in air speed or increased loads, and the blades of the propeller or propellers will be automatically o1' manually adjusted, as desired, to apply the force of the propelling engines in accordance withchange of conditions; and the fuel supply to the engine will be increased to compensate for a tendency to slow down and stall, whereby, also, theair speed of the aircraft may be varied'by varying the pitch of the propeller, the engine operating at its most economical speed.

invention, applied to aircraft, are,1st, economy, in maintaining the most economical pitch of the propeller blades for the engine speed and air speed selected by the pilot, without vibration; 2nd, safety, in developing full automatic control inaccordance with changes of conditions, and regardless of pilots attention or inattention and' also while landing), yet reserving fullmanual f y control in an emergency and resumption of automatic control when the emergency has passed; 3rd,l convenience, in permitting the pilot to attend to other matters While in l flight, as navigation, stability, elevation, etc.; in permitting rapid warming up, without the annoying wind stream; in taking off, permitextent that the propeller pi The three primary ends attained by myto compensate for 'the decrease of l.

1930. Serial No. 454,162.

ting ap lication of power most effectively to attain flying speed quickly, etc.

Thus, :t'or instance, in the special application of my invention to airplanes or airships, among my objects are:

First, to allow the pilot of an airplane or the chief engineer in the control cabin of a dirigible full manual control of the pitch of the propeller blades, so that the pitch can be increased to the maximum to attain maximum speed when necessary, oi' may be adjusted to a neutral or reversed position to act as a brake, or may be adjusted manually to any intermediate position;

Second, to allow the airplane pilot, or the chief engineer of a dirigible, without the interposition of individual engineers' in the several enginegondolas, to have full manual oontrol of the speed of the several engines, or all simultaneously, yet to allow automatic con- 7 trol of each engine within itself,'so that any tendency of a particular engine, or of all of them, to deviate from anyset speed will be self-corrected;

Third, to automatically control the itch of the propeller blades in accordance wit the air speed of the aircraft, so that, for instance, should an airplane thus equipped be climbing at such an angle that it loses speedto an does not cor- 3 the pro er loses its eiiiciency (such a condition ing preliminaryY to a spin), the pitch' of the proeller blade will be decreased to ap v1y the orce available more strongly and e ciently to the air, thus tending to attain a pitch'c'orl responding to the rate of advance.' 0n the contrary, if the air speed increases, the pitch f the propeller blades is correspondingly increased; 9

' Fourth, 'to provide a control for the fuel feed to the engines' which does not interfere with manual controlthereof, but which may be made automatica respond to the air speed, a

y res nsi've to changes in engine speed,'so that, fd): instance, Should 95 a climb beso steep that the-engine tends to stall, the decrease in engine speed (or the v tendency to decrease) will cause additional fuel to be supplied to the engine of to develop alhigher speed orl greater power.

On the contrary, a tendency 1n an engine to speed up will be counteracted by lessening the fuel supply. As a result, the engines will operate at the desired economical speed for which they are set, at highest eiciency. The result isl particularly desirable for Dieselpowered airplanes;

Fifth, to provide a combination of air speed and engine speed controls, whereby each may operate to control the appropriate part of the propulsion mechanism, as the occasion requires, cooperating and maintaining a relative balance, all automatically, yet all subject to the manual'control of the pilot at any time; l

Sixth, to provide such a control system, which is applicable to single-engine planes or aircraft generall or to multiple-engined aircraft, and speci cally to avoid the necessity of an engineer and relief for each individual engine in li ghter-than-air craft;

Seventh, to provide such control means of small size and weight, such that the operating parts associated with the propeller can be inthe propeller hub, without the adding considerably to the or to the corporated in necessity of weight of the propeller as a' whole, centrifugal effect thereof.

Other objects, and more particularly such as refer to the mechanical details of my invention, and the adjustment thereof, will be readily ascertained 'from a study of the attached drawings, wherein my invention is shown in a number of illustrative forms, and as now preferred by me, and of this specication and the claims which terminate the My invention comprises the novel parts and the novel combination and arrangement thereof, as shown in the accompanying drawings, described in this specification, and as will be more particularly pointed out in the claims at the end of this specilication.

Figure 1 is a side elevation of my propeller hub, mounted upon the end of the engine shaft, the blades themselves being broken'olf.

Figure 2is an axial section through my device, taken-from substantially the same view point as Figure 1.

Figure 3 is a section through my device, taken substantially on the line 3-3.of Figure 2.

Figure 4 is a transverse section through my device on the line 4--4 of Figure 3.

Figure 5 is a diagram of my device, with a lsingle speed control only,and intended for application tol a single propeller, that is to say, the simplest form illustrating that phase of the principles of my invention.

Figure 6 illustrates my inventior dia rammatically in a form ap licable to mu tiple- -engined planes, but wit a single speed-control lonly.

Figure 7 illustrates'my invention diagramdive,

matically in a form which is suitable for multiple-engined lanes and with two speed control devices, or instance, an air speed control andan engine speed control.

Heretofore control of the air speed of aircraft while in flight has been directly and solely b means of variation of the engine speed. e pitch angle of the propeller blades was a constant. An engine operates best at a given speed, and if the pitch angles of the propeller blades are not set so as to correspond to the speed of the engine, the utilization of power is not as efficient as it should be. The air speed o f the craft (within the capability of the engine) is dependent u on the pitch angle setting of the propeller b ades. It follows, then, with the automatic adjustment of the ropeller blades, that the engine speed may be kept constant (within limits defined by its capabilities) and the power developed at such engine speed be most eiliciently applied in accordance with air speed by changing the pitch in accordance with changes of air speed. The former variable factor, engine speed, is thus made the constant, and control of air speed is achieved not by variation of engine speed, but by variation of the pitch angles.

This control will be sufficient so long as the load placed upon the engine is within its capabilities, but if the load increases, as by a steep climb, to the point where the engine, at the given speed, would stall, it is essential that it develop more power to prevent stalling. On the other hand, if the load decreases, as by diving, the engine would tend to race. Under such conditions the engine speed must be varied; in the first instance, it must be increased, by supplying more fuel; in the second instance, it must be decreased, by supplying less fuel. For such uses I provide automatic controls linking the engine fuel feed control (throttle valve) with an engine speed device, whereby changes in engine speed are compensated by changes in the amount of fuel supplied.

There is thus a combination of controls. Assuming a given engine speed and air speed, there will be a given fuel feed, dependent on the engine speed, and there will be a given pitch setting, dependent on the air speed. Should the aircraft start to climb, it will tend to lose air speed, and the pitch will decrease. If the climb is sharp enough, but not otherwise, the added load will make itself felt in a tendency for the engine to slow down, which will increase the fuel feed to maintain controlled engine speed. Should the ship instead of climbing, the increase in air speed would increase the pitch, but when the load on the engine lessenedy to a point where it tended to speed up, the fuel supply is automatically cut down, and the engine tends to slow down again.

None of this prevents the pilot from chang- .ing-his propeller pitch at will, or from supplymg more or less fuel to change his engine speed.l I have provided a manual control for each individual engine, or for all engines, whereby the engine speed can be varied from idlingv to maximum speed, and other manual controls whereby the pitch of the blades of any given propeller, or all propellers, can be varied at will, from neutral or reverse to the maximum. By the automatic controls the i pilot is assured that the air speed and ensuchI as navigation.

Heretofore, the term engine has been employed to designateA the prime source of propulsion of the aircraft. and that term will be so used hereafter, to distinguish from an electric motor forming part of the control mechanism.

In effect, insofar as control of the pitch of the propeller blades is concerned, my lnvention comprises an electric motor, preferably mounted in the rotatable hub of a propeller, which is connected to the oscillatable blades, likewise mounted in this hub, to turn them in one direction lor the other when the motor 1s energized.,l The. electric motor is reversible, and motor `reversing means are provided, whereby the same may be reversed at will, these usually taking the form of a reversing switch.A Motor control means are provided, these being of two parts balanced one against the other. One of these parts is controlled by a speed-responsive device, such asa winddriven generator, the output of which is governed by the air speed of the aircraft, and

the other part of the electrical'control may be' controlled by a rheosta or like means,

which is responsive to variations in the position of the blades .corresponding to diil'erences of; pitch. For normal operation, these two 'parts of the electrical control are' balanced one against the other, but when one becomes the stronger', for instance, if the air speed increases, the part corresponding thereto lbecoi'nes the stronger and-.overcomes the other part, controlled by the pitch of the blades, .and the reversing means is moved from its normally inoperative position` int'o position to operate the motor one way or the .y other tqcompensate for" the change in the electrical control means. t A s'soon as proper compensation is'- made the reversing means reverts'to its normal inoperative position.

Insofar as the engine controlis concerned,

my -invention comprises av deviceoperative to increaseor diminish the fuel lsupply-to the engine, the same being governed by a like balanced two-part electrical control, one part 'controlled by a speed-responsive device such as a generator driven from the engine itself,

' the output'of whichis governed by the speed electrical control may be controlled by the same rheostat, responsive to variations in the pitch of the propeller blades.

ySo loiig as the aircraft is operating at an air speed which is in consonance With the pitch of the propeller blades, and presumably that pitch which most economically develo s that air speed, no change will result. Shou d the air speed of the craft fall oil", immediately and Wit out attention from the pilot the air speed control member will come into opera tion to lessen the pitch compensably to the new air speed. rIhe engine speed control is not affected thereby, and the engines speed is unchanged. Similarly, when the air speed of the craft increases, the propeller pitch increases, without affecting the engine speed. A

In cach case the reaction through the rheosta-t brings the two parts of the air speed control into equilibrium to stop the pitch adjustment until some further change occurs.

So long as the engine speed is adequate to the load it will run at selected speed which is presumably the most economical one. Should the engine speed tend to decrease, immediately and without attention from the pilot the engine speed control will come into operation to increase the fuel supply compensably to the added load. In effect the engine speed is thereby maintained at the speed which is most economical for the load placed upon it. Similarly, when the engine speed increases, the fuel supply is lessened. In each such case the change in engine speed oc casions a change-in air speed, as is nowal- Ways the case, but the reaction through the same rheostat brings the engine speed control into-equilibrium again, to stop further change in the fuel supply until some further change occurs.

While my invention may take various mechanical forms, it vwill be best understood if one of those forms, as illustratedin Figures 1 to 4 inclusive, is understood, and I `will therefore describe this form, not in any sense .as limiting myself to this precise form,but as illustrative of a forn which may be vari- Ously changed and adapted to the necessities of a given situation. f'

The propeller blades 1 and 1 areindicated only .by thei -inner ends, and terminatezin Shanks 10, w ich are received in suitable bearings 21 in a rotatable propeller hub body 2, which is suitably keyed and secured upon the projecting end of an 'engine shaft 29. The mounting of the propeller blade for oscillations may be' any that`is desired., and I and to counteract the centrifugal force, tending to throw the blade outwardly. This cap 2O is threaded in the hub, 2. -In this form the bearings 21 are interposed between the sleeve 11 and the cap 2() and the hub 2.

In order to oscillate the blades 1 and 1f simultaneousl and equally, their respective gears 13 are 1n mesh with worm pinions 14 on shaft 15 (see Figure 3) and on the outer end of these shafts 15 are gears 16, which in turn are both in mesh with a driving gear 17, which is driven from a motor 18, secured upon a plate 23, which is secured upon the face of the hub 2. For purposes of adjustment in the shop, the shaft 19 of the electric motor 18 may project into a sleeve 24, likewise secured upon the propeller hub 2, or within an extension thereof, and be provided with a socket 19', wherein may be 1nserted the squared end of a crank to permit turning of this shaft 19. The end of the sleeve 24 is closed by a suitable plug 26. The arrangement just described produces a balanced hub, with the weight concentrated at the axis, so far as possible, reducing the centrifugal effect to the minimum.

Associated with one or with both of the propeller blades, but preferably with one only for each propeller, is a rheostat. This is conveniently associated with one of the worm gears 13, as may be seen in Figure 3. This rheostat may consist of a plurality of segments 31 corresponding to varying vresistances, and a return terminal complemental to all of the segments 31, designated by the numeral 32. Suitable brushes are provided in position to contact with the segments 31 and the return terminal 32 respectively, and these leads extend through the body of the hub 2 to rings 3 and 30 respectively (see Figures 2 and 3) which are mounted upon the outside of the hub in position to be contacted by the respective brushes 33 and 34. Similarly, the leads to the motor 18 may extend through the body of the hub 2, to the respective rin 4 and 40, which in turn are contacted by the fixed brushes 41 and 42 respectively. By these or like means, a current is conducted to and from the rheostat and thev Lnoktor, mounted within the rapidly rotating The rings and brushes referred to above should be suitably protected from the weather, and as an instance of such protection, I have illustrated the apron 28 secured to thel nose of the fuselage 28, and received beneath a circular flange 27 on the hub 2 or the extension 27 secured thereto and supporting the several rings 3, 30, 4 and 40. The apron, coupled with the centrifugal effect of the flange 27', will keep water out of the electrical connections just described.

It may be noted here that the parts are all so arranged that it is only necessary to remove the plate 23, whereupon the retaining nut 22 can be removed and the entire hub may be slipped of of the engine shaft 29; the rings 3, 30, 4 and 40 all come olf with the hub, and the brushes and brush-holders may be left attached to the nose of the fuselage. No part is in contact with the engine shaft 29. This makes it a comparatively simple job to remove and replace a propeller.

Having in mind the mechanical structure described', We may now refer to Figure 5, which shows the connection of the mechanism and the electrical devices heretofore referred to, in the control system. The main source of current is illustrated in the mains 5, which is illustrated as a source of direct current, although alternating current might be employed. A lead 53 through a resistance 54, which may be adjustable for each installation, but which would be fixed when once adjusted, connects the rheostat 31 with one side ofthe main 5 through the brush 34 and the ring 30. The rheostat is connected to the other side of the main through the ring 3, the brush 33 and the leads 55 and 56.

Between these leads 55 and 56 is included one part of a two-part balanced electrical control device, generally indicated by the numeral 6, and the part which is included between the leads 55 and 56 is designated as the solenoid 65. An indicator or galvanometer is also indicated in the lead 56 at 57.

Connection between the motor 18 and the mains 5 is accomplished through leads 7 0 and 71, which connect with the respective brushes 42 and 41; these leads 70 and 71 connect with terminals 72 and 7 2a on the one hand, and 73 and 73a on the other hand, of a motor reversing mechanism, which conveniently takes the form of a reversing switch 7. Normally, the movable contacts of this switch 7 are held in a neutral position, but when moved to the right, as seen in Figure 5, connection is established between the terminals 72 and 73, and the two sides of the main 5,

yand current is delivered to the motor 18, tending to turn it in a given direction. If the movable contacts of the switch 7 are moved to the left, as seen in Figure 5, contact is established between the terminals 72a and 73a, and the two sides of the main 5, in such a way as to deliver current tothe reversible motor 18 in the opposite direction, causing it to reverse, and according to the direction of rotation of this motor, the blades 1 and 1 of the propeller are oscillated in one direction or the other.

This motor-reversing means, or reversing switch 7, is under the control of the two-part balanced electrical control heretofore referred to, and shown at 6. One part of this, as has been pointed out, consists of the .solcnoid 65, the strength of the current through the same beingv a function of the position of the blades 1 and 1 communicated through the rheostat 31. The other part, 68, is conwould 'in some other manner be driven at a speed which is a function of the air speed of the-craft. Its current output is therefore variable. For a given speed of the generator 8, and a given setting of the blades 1 and 1, the force of the solenoid 65 will balance the force of the opposed solenoid y68, and the common core will remain in equilibrium. Any increase in one force over the other will cause a movement -lof the core 60 towards the stronger, and will result in movement of the switch arm 6l, pivoted at 63, to which the solenoid core 60 is connected..

This switch arm 61 is connected by a lead 62 to one side of the main 5, and its swinging endy 61 is'adapted to contact with Aone of two terminals 64 or 66. These in turn are connected by leads to one side of the respective solenoid coils 64 and 66', the opposite side of which is connected through a common lead 67 to the main 5 so as to be opposite insign to the lead 62.

Any increase in the strength of the solenoid 68, for instance, dueto increased air speed of the aircraft, will result in upward move- Vment of the solenoid core 60 and contact between the terminall 61 and the terminal 64, which will energize the solenoid 64 and cause movement of the core 69, which is connected through the arm 69 to move the connected series of movable contacts 79 of the reversing switch 7, in such a direction as to cause current to ow through the 'terminals 72a and 73a,whichenergizes the motor 18, causing it" to increase the pitch of the pro'- peller blade,` so that it bears the most efvcient relationto the speed of the aircraft.

'the propeller blades may be kept in neutral,

and the engine will be warmed up without any load being .placed upon the propeller blades. Inv consequence,- it -will not be necessary to employ chocks under the wheels, and there will be no slip-stream of air past the fuselage. When the pilot is ready to take off, the pitch ofthe blades is increased gradually until he attains suiiicient speed for takin off, and when once in the air, having attained iiyingspeed, the pilot may close the switch 6 and. release the control-rod 79 of l the switch 7, whereupon -the automatic controls will govern. y

It will benoted at 8O that there is a rheostat control for thecircuit 811, Which-includes for obtaining adjustment between the the field coil 82 ofthe generator 8. Variation of the strength of current in the field coil 82 varies the output voltage of the generator 8, and consequently, varies the range of strength of the solenoid coil 68. By these means, or equivalent means, the point at which equilibrium between the coils 68` and of the air speed electrical control can be varied at will, and thus is provided a'means ropeller pitch and the air speed of the cra t.

It is quite evident that this device may be employed alone and without any automatic control for the engine speed, leaving the control of the engine speed, as heretofore, under the manual control of the pilot through a throttle lever, but since variations in the pitch of the propeller merely com nsate for changes in air speed of the cra t, and since there are speeds both low and, high which may become dangerous, and it is necessary to maintain the air speed of the craft, particularly airplanes, between certain limits, it is desirable to provide an automatic control forl the engine fuel supply. However, before taking up the engine speed control, it is desired to point out how the air speed control can be applied to several motors.

Refer now to Figure 6, wherein the parts are arranged to control the propellers of two` engines. The two electric' motors 18 are shown,one for each propeller, and to distinguish them, they have been given the sufiixed letter R or L for right and left, as the case may be. Similarly, the rheostats 31 have been distinguished by the same suffixes. As to lthese devices, and as to the motor reversing means or switch 7, the devices are like that already described, and it does not seem necessary to go through the description again, since'the parts are similarly numbered, but distinguished where necessary'by the suiiixed letter R or L.

lt will be noted, however, that there is but one balanced two-part control, and but one generator 8. The generator 8, as before, is connected to one-half ofthe two-part control electrical control, including in its circuit the solenoid coil 68. rllhe opposing coil 65 is not-directly connected to either one of the rheostats 31B. or 31L, but is connected rather by means ofa double-throw switch 65', which,` when thrown in one direction, connects the coil 65 with the leads 55B and 56By respectively, or when thrown in the opposite direction, connect with the leads 55L and 56L. lThe purpose of the switch at 65 is to make it possible to control the current passing through the coil 65 by one or the other of the rheostats 31, but not by both at any one time. If one motor, or any of the connections thereto, should fail to 'function properly, it is possible to switch the controls over to Ithe other propeller and its motor, and to emake the Arheostat in the other propeller control the les two-part balanced control at 6. Assuming the switch at 65A to be thrown so as to control the device through the righthand propeller, the operation will be just as described before with an exception to be noted, and while current will be passing throu h the rheostat 31L, it will not affect any o the controls.

The exception noted is that the electrical control at 6 is not connected to the switch 7 R, which'directl controls the direction of the motor 18R. he motor 18B. may at all times be manually controlled through the switch 7 R, but these individual switches, such as 7B, are not automatically controlled. Instead there is provided a master reversing switch designated 7 M.' Such a switch is substantially identical with the individual switches, and has like terminals connected in the same circuit, but it is also provided with additional contacts corresponding in number to the number of propellers the pitch of which is to be controlled. These contacts are indicated at 7 3L and 7 3R. 73B is con-- nected in the'lead 70H, while the contact 7 3L is connected in the lead 7 0L.

It will be evident that, without the contact 73B for instance, if the master switch 7M Were to be moved to the right, the contacts 72a and 73a would be energized, all other contacts being left dead, and this would, en-

- ergize the left motor, but in order to energize the right motor also,"so that the pitch of the blades of both propellers will be adjusted simultaneously and equally, the additional contact 7 3R is provided which is connected into the controls for the right motor 18B.

The master switch 7M is controlled as before by the opposed solenoids 64 and 66', en-

ergized as before by the movable switcharm 61.

So far as the operation is concerned, then, ,the doublethrow switch merely determines whether the right propeller or the left propeller and its rheostat is to control. The master switch 7M is provided for reversing the motors, and reverses both of them simultaneously by means of an additional pair of leads which are included, so that three contacts are made, one a common contact and one for each ofthe electric .motors in the individual propeller hubs. The entire-automatic control, as before, may be cut out by leaving open the switch 6. Adjustment of the strength of the air speed solenoid 68 is obtained by adjustment of the rheostat at 80, and the device is just like that previously described, except that it takes care of two propellers.

I'n Figure 7 is shown an arrangement for employment with an aircraft having two engines and having both the air speed control and the engine-speed control. The air speed control for dual engines has already been explained, and the addition of the engine-speed control does not affect the operation of the air speed control.

Associated with each of the propelling engines is an engine-driven generator 9, the

Any increasein the strength of the current passing through the rheostats 31 increases the strength in the respective rheostat coils 95, moving their cores inward, and depressing the corresponding throttle members 93, which would be so connected to the fuel supply for their respective propelling engines .that such movement would increase the amount of fuel supplied, assuming an increase in current through the rheostats to be associated with an increase' of pitch in the respective propellers. a

Adjustment of the current strength through the fields 96L and 96B- respectively of the generator 9 may be accomplished for the individual generators by means of a rheostat 94L and R, and this adjustment can be put into effect while the two engines are in operation. In this connection, it will be borne in mind that the automatic engine speed control is accomplished for both of` the engines, and each in turn is controlled by the @pitch of the pro eller lwhich it drives, whereas, the control o the pitch of both propellers was from a single, wind-driven, generator only. However, when it is desired to increase or decrease the engine speed of both engines simultaneously, this may be accomplished by means of the master rheostat 94M. .When the maximum resistance is cut into the line by the individual rheostats 94L or 94B, the control may be through the master rheostat 94M, arranged in parallel to the individual rheostats, or the individual rheostats may be set for a selected resistance, and the control mainly effected through the master rheostat 94M. Switches 97L and 97B are connected in the4 individual lines branching from the master rheostat 94M; with these open the master control is ine'ective, but control may be had of the individual engines through the individual rheostats 94L or 94B. It is my intention that the condition arising when the switches 97L and .97B are open,.and allI resistance of the-individual rheostats 94L and 94B is cut out, shall result in idling the engines, leaving their individual control to the pilot through the rheostats 94L and 94B, until such time as the switches .97L 'and 97B I `ergy 5 engine speed), the pilot need only control the rheostat at 80 to adjust the propeller pitch with relation to the air speed of his craft, and need only regulate the lrheostat at 94M to ob- Btain control ofthe engine speed of his craft manually. Should he desire to change the .propeller pitch .momentarily, this may be done by means of the master reversing switch 7M,and as stated before, control of the engine speed is effected through the rheostat 94M, 15

though it will be evident that control.l may be had manually of the members 93, controlling the supply of fuel to the individual engines Without disturbing the setting. of the automatic control means, or setting the same into operation.

Itwill be evident that various parts, such as the levers 61 and 92, will be properly balanced, and guarded against failure in any position of the plane. Similarly, motor brushes will be guarded against failure by reason of any centrifugal effect, and the device Will generally be put into such mechanical form and so mounted as will best suit the purpose. My invention, or the pertinent portions thereof, will find many uses. One of the problems in gyroscopic control of airplanes is to develop a source of constant potential current. A control such as this will regulate the pitch of the blades of the propeller which drives the wind-driven generator itself, as well as ythe blades of a propelling engine, and consequently, if the pitch ofthe blades of the wind-driven'generator are regulated in accordance With'the air speed of the craft, it is possible to produce constant potential en- The principles of the device may be adapted also to marinel craft, controlling the pitch of propeller blades 'in accordance with the speed of a vessel through the water, and controlling the ,fuel supply to the engine to Y accord with the pitch of the propeller blade.

What I claim as my invention is: l

1. In an aircraftin combination with arotatable mount and propeller blades oscillat- .ably mounted' therein, means automatically operating in 'accordance with variations in the air speed of the aircraft to compensably oscillate said blades'.

2. In an aircraft,'in` combination with a rotatable propeller mount and propeller blades oscillatably mounted therein, means operable y in accordance With variations inthe air speed of the aircraft and controlled thereby to compensably oscillate said blades. 3. In combination with the driving engine of anaircraft, a rotatable mount and propeller blades voscillatably mounted therein, means operable in accordance withvariations in the 65 air speed of the aircraft to compensably oscillate said blades, and other means' operable in accordance with the positions assumed by said blades to vary the enginesrfuel supply to maintain controlled engine speed. l

4. In an aircraft, in combination with a plurality of rotatable mounts and propeller blades oscillatably mounted in each, means operable in accordance with variations in the air speedof the aircraft to compensably oscillate all blades simultaneously and correspond- ,ingly in amount.

5. A centrol system comprising a source of y current supply, a rotatable propeller hub,`v

oscillatable blades mounted therein, a motor operable to oscillate said blades, a motor reversing means, a two-part normally balanced electrical control for said motor reversing means, means responsive to variations in the position of the blades to control one part of said control, andl means responsive to variations in the vehicles speed to control the other part thereof.

6. Aimotor control system as in claim 5, including electric operating means for moving said motor reversing means. .into positions corresponding to operation in each direction, and a normally open selective switch for energizing said operating means, when the switch is closed, said switch being operable by the electrical control means.

7. A motor control system as in claim 5, including electric operating means for moving said motor reversing means into positions correspondingto operation in each direction, and a normally open selective switch for energizing said operating means, `when the switch is Closed, said switch being operable by the electrical control means, and a manual switch in thecircuit of said selective switch.

8. A controlsystem comprising a source of current supply, a rotatable propeller h ub, oscillatable blades mounted therein, a motor operable to oscillate said blades, a motor reversing means, a two-part normally balanced electr-ical control vfor said motor reversing means, means responsive to variations in the position of the blades to control one part of said control, and means responsive to varia- `tions in the vehicles speed to control the electrical control for said motor reversing of termlnals each corresponding to and con- 4.nected to its respective solenoid, and adapted means, means responsive to variations in the position of the blades to control one part of said control, and means responsive to variations in the vehicles speed to control the other part thereof, said motor reversing means being manually operable, and means manually operable at will to eliminate the said electric control means.

11. A control system as in claim 5, the motor being located in the rotatable hub, and the blade-controlled control means including -a rheostat located in the hub and operable by oscillations of a blade therein.

12. -A control system as in claim 5, the electrical control forthe reversing means comprising a pair of opposed solenoids connected to the motor reversing means, each of said solenoids being connected to one side of the electric source, a selective switch connected to the other side of the electric source, a pair of terminals each corresponding to and connected to itsirespective solenoid, and adapted to be contacted by said selective switch to complete the circuit through its respective solenoid, and means connecting said 'switch to the balanced electrical control for operation thereby.

13. A'control system as in claim 5, the elec- .trical control for the reversing means comprising a pair of opposed solenoids connected ,to the motor reversing means, each of said ysolenoids being connected to' one side of the `electric source, a selective switch connected to Y the other side of the electric source, a pair to be contacted by said selective switchto complete the circuit through its respective solenoid, and means connecting vsaid switch to the balanced electrical control for operation thereby, and a cut-out switch in said selective switch-solenoid circuit. 1

14. An aircraft control system comprising a source of electric current supply, a plurality of rotatable propeller hubs, oscillatable blades mounted in each thereof, a motor operable to oscillate the blades of each hub, a motor reversing means corresponding to each motor, a master motor reversing means connected in the circuit of each motor, a twopart normally balanced electrical control operatively connected for actuation of said master reversing means responsive to variations in the speed of the air craft to control one part of said control, and means responsive to variations in the position of a propeller blade to control the other part thereof..

15. A control system as in claim 14, including means to ad]ust the balance of the two parts ofthe electrical control', one part relative to the other. i

16. A control system as in claim 14, each propeller having the last-mentioned means,

and a switch to connect any one of said means therefrom, propeller blades to operate the two-part electrical control, and

to disconnect all others.

17. In aircraft, a control system comprising a fuel supply means, a rotative air propeller, blades mounted therein and adjustable in pitch, means for automatically adj usting the pitch of said blades inaccordance with variations in the air speed of the aircraft to compensably oscillate the blades, and means automatically responsive t0 changes in pitch of the blades to compensably adjust the fuel supply means to maintain a controlled speed to the engine supplied thereby.

18. A control system as in claim 17 including a generator the output of which is a function of the rate of engine speed, a two part electrical control means comprising the means connected to adjustthe fuel supply,

one part thereof being controlled by the output of said generator, and the other part being controlled by the change of pitc of the propeller.

19. A control system as in claim 17, and in combination therewith, means responsive to change in the relative speed of the vehicle to compensablyadj ust the propeller pitch.

20. A control system as in claim 17, for controlling the fuel supply to a plurality of engines, and in combination therewith,

22. In an aircraft, in combination with al driving engine, a rotatable mount driven oscillatably mounted therein, means automaticall operating in accordance with variations 1n the pitch'of the propeller blades to compensably vary the engines fuel supply, and means driven by said engine coo rating with said first means to compensa ly vary the fuel supply in accordance with the engine speed, to maintain constant engine speed.

Signed at Longview, Cowlitz County, Washington, this 14th day of May, 1930.

FRED w. FINDLEr means in addition to such automatic 'fuel' control system for aircraft compris- 

